Micro-porous conduit

ABSTRACT

A porous conduit may be suitable for use in treating a tissue site, and may include a central lumen and a porous wall positioned substantially concentric about the central lumen. The porous wall may have an open porous structure that may define a plurality of interconnected pores in fluid communication with one another. As part of a system, the porous conduit may be used with a manifold adapted to be positioned at a tissue site, a sealing drape adapted to cover the manifold to provide a sealed space relative to the tissue site, and a therapy device including a reduced-pressure source. The porous conduit may be disposed in the sealed space and in fluid communication between the sealed space and the reduced-pressure source.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/709,154, filed Sep. 19, 2017, which is a continuation of U.S. patentapplication Ser. No. 14/173,947, now U.S. Pat. No. 9,795,515, filed Feb.6, 2014, which claims the benefit, under 35 USC § 119(e), of the filingof U.S. Provisional Patent Application No. 61/782,713, entitled“MICRO-POROUS CONDUIT,” filed Mar. 14, 2013, each of which isincorporated herein in its entirety by reference for all purposes.

FIELD

This disclosure relates generally to medical treatment systems and, moreparticularly, but not by way of limitation, to micro-porous conduits,dressings, and systems suitable for use in treating a tissue site.

BACKGROUND

Depending on the medical circumstances, reduced pressure may be usedfor, among other things, reduced-pressure therapy to encouragegranulation at a tissue site, draining fluids at a tissue site, closinga wound, reducing edema, promoting perfusion, and fluid management.Common conduits, dressings, and systems may be susceptible blockagesthat can cause a reduction in the effectiveness of the therapy or acomplete loss of therapy. Such a situation can occur, for example, ifthe amount of fluid in the system exceeds the fluid capacity of thesystem. Blockages in conduits, for example, may prevent reduced pressurefrom reaching the tissue site and/or prevent accurate measurement of thereduced pressure at the tissue site for reduced pressure control. Thus,improvements to conduits, dressings, and systems that may enhancereliability are desirable.

SUMMARY

Shortcomings with certain aspects of tissue treatment dressings,systems, and methods are addressed as shown and described in a varietyof illustrative, non-limiting embodiments herein.

In some embodiments, provided is a system for treating a tissue sitethat may include a manifold, a sealing drape, a porous conduit, and atherapy device. The manifold may be adapted to be positioned proximatethe tissue site. The sealing drape may be adapted to cover the manifoldand the tissue site to provide a sealed space between the sealing drapeand the tissue site. The porous conduit may be adapted to be in fluidcommunication with the manifold and the sealed space. The porous conduitmay include a central lumen, a first porous wall, a barrier layer, and asecond porous wall. The first porous wall may be positionedsubstantially concentric about the central lumen. The first porous wallmay have an open porous structure defining a plurality of interconnectedpores in fluid communication with one another. The barrier layer may bepositioned substantially concentric about the first porous wall. Thebarrier layer may be comprised of a non-porous material. The secondporous wall may be positioned substantially concentric about the barrierlayer. The second porous wall may have an open porous structure defininga plurality of interconnected pores in fluid communication with oneanother. The barrier layer may substantially preclude fluidcommunication laterally between the first porous wall and the secondporous wall. The therapy device may be adapted to be in fluidcommunication with the porous conduit.

In other embodiments, provided is a system for treating a tissue sitethat may include a manifold, a sealing drape, a porous conduit, and atherapy device. The manifold may be adapted to be positioned proximatethe tissue site. The sealing drape may be adapted to cover the manifoldand the tissue site to provide a sealed space between the sealing drapeand the tissue site. The porous conduit may be adapted to be disposed inthe sealed space in fluid communication with the manifold and the sealedspace. The porous conduit may include a central lumen and a porous wall.The porous wall may be positioned substantially concentric about thecentral lumen. The porous wall may have an open porous structuredefining a plurality of interconnected pores in fluid communication withone another. The therapy device may be adapted to be in fluidcommunication with the porous conduit. The therapy device may include areduced-pressure source and a pressure sensor. The reduced-pressuresource may be adapted to be in fluid communication with the centrallumen, and the pressure sensor may be adapted to be in fluidcommunication with the porous wall.

In other embodiments, provided is a system for treating a tissue sitethat may include a manifold, a sealing drape, a porous conduit, and atherapy device. The manifold may be adapted to be positioned proximatethe tissue site and to distribute reduced pressure to the tissue site.The sealing drape may be adapted to cover the manifold and the tissuesite to provide a sealed space between the sealing drape and the tissuesite. The porous conduit may be adapted to be disposed in the sealedspace in fluid communication with the manifold and the sealed space. Theporous conduit may include a central lumen, a first porous wall, abarrier layer, and a second porous wall. The first porous wall may bepositioned substantially concentric about the central lumen. The firstporous wall may have an open porous structure defining a plurality ofinterconnected pores in fluid communication with one another. The firstporous wall may be comprised of bonded particles defining theinterconnected pores. The bonded particles may be sintered polymerparticles. The barrier layer may be positioned substantially concentricabout the first porous wall. The barrier layer may be comprised of anon-porous, liquid impermeable material. The second porous wall may bepositioned substantially concentric about the barrier layer. The secondporous wall may have an open porous structure defining a plurality ofinterconnected pores in fluid communication with one another. The secondporous wall may be comprised of bonded particles defining theinterconnected pores. The bonded particles may be sintered polymerparticles. The barrier layer may substantially preclude fluidcommunication laterally between the first porous wall and the secondporous wall. The therapy device may be adapted to be in fluidcommunication with the porous conduit. The therapy device may include areduced-pressure source, a fluid instillation source, and a pressuresensor. The reduced-pressure source may be in fluid communication withthe central lumen, the fluid instillation source may be in fluidcommunication with the first porous wall, and the pressure sensor may bein fluid communication with the second porous wall.

Other aspects, features, and advantages of the illustrative embodimentswill become apparent with reference to the drawings and detaileddescription that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of this specification may be obtained byreference to the following detailed description when taken inconjunction with the accompanying drawings wherein:

FIG. 1 illustrates an embodiment of a system for treating a tissue site,with a portion shown in cut-away view, depicting an illustrativeembodiment of a porous conduit according to this disclosure;

FIG. 2 illustrates a cross-section view of an external end of the porousconduit of FIG. 1 taken at line 2-2 in FIG. 1;

FIG. 3 illustrates a cross-section view of an insertion end of theporous conduit of FIG. 1 taken at line 3-3 in FIG. 1;

FIG. 4 illustrates a cross-section view of another embodiment of aporous conduit suitable for use with the system of FIG. 1;

FIG. 5 illustrates a cross-section view of another embodiment of aporous conduit suitable for use with the system of FIG. 1; and

FIG. 6 illustrates another embodiment of a system for treating a tissuesite, with a portion shown in cut-away view, depicting the porousconduit of FIG. 1 adapted for use with a conduit interface and amultiple lumen conduit.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following detailed description of the non-limiting, illustrativeembodiments, reference is made to the accompanying drawings that form apart hereof. Other embodiments may be utilized, and logical, structural,mechanical, electrical, and chemical changes may be made withoutdeparting from the scope of this specification. To avoid detail notnecessary to enable those skilled in the art to practice the embodimentsdescribed herein, the description may omit certain information known tothose skilled in the art. The following detailed description is providedwithout limitation and with the scope of the illustrative embodimentsbeing defined by the appended claims.

Referring to the drawings, provided is a system 100 for treating atissue site 104 that may be suitable for use with reduced pressure. Thetissue site 104 may extend through or otherwise involve an epidermis106, a dermis 108, and a subcutaneous tissue 110. The tissue site 104may be a sub-surface tissue site as depicted in FIG. 1 that extendsbelow the surface of the epidermis 106. Further, the tissue site 104 maybe a surface tissue site (not shown) that predominantly resides on thesurface of the epidermis 106. The system 100 may provide therapy to, forexample, the epidermis 106, the dermis 108, and the subcutaneous tissue110, regardless of the positioning of the system 100 or the type oftissue site. The system 100 may also be utilized without limitation atother tissue sites.

Further, the tissue site 104 may be the bodily tissue of any human,animal, or other organism, including bone tissue, adipose tissue, muscletissue, dermal tissue, vascular tissue, connective tissue, cartilage,tendons, ligaments, or any other tissue. Treatment of the tissue site104 may include removal of fluids, e.g., exudate or ascites. Asdescribed below, components of the system 100 may be fluidly coupled toeach other to provide a path for transferring fluids (e.g., liquidand/or gas) between the components. As used herein, unless otherwiseindicated, “or” does not require mutual exclusivity.

Referring to FIGS. 1-3, in some illustrative embodiments, the system 100may include a dressing 116, a porous conduit 120, and a therapy device124. The dressing 116 may include a manifold 128 and a sealing drape132. The manifold 128 may have a first side 134 and a second side 136.The first side 134 of the manifold 128 may be adapted to be positionedwithin, over, proximate to, adjacent to, facing, or in contact with thetissue site 104. The manifold 128 may take many forms, and may be anysize, shape, or thickness depending on a variety of factors, such as thetype of therapy being implemented or the nature and size of a particulartissue site. The manifold 128 may, for example, be cut or otherwiseshaped to fit the particular size and shape of the tissue site 104 inany suitable manner.

The manifold 128 may be a substance or structure capable of applyingreduced pressure to, delivering fluids to, or removing fluids from thetissue site 104. In some embodiments, the manifold 128 may be used todistribute fluids such as medications, antibacterials, growth factors,and various solutions to the tissue site 104. For example, the manifold128 may be a porous and permeable foam or foam-like material including aplurality of flow channels or pathways that distribute fluids to andremove fluids from the tissue site 104. The manifold 128 may include,without limitation, devices that have structural elements arranged toform flow channels, such as, cellular foam, open-cell foam, poroustissue collections, liquids, gels, and foams that include, or cure toinclude, flow channels. Additionally, the manifold 128 may be a gauze,felted mat, or any other material suited to a particular biologicalapplication.

In some embodiments, the manifold 128 may be a porous, hydrophobicmaterial such as a polyurethane, open-cell reticulated foam manufacturedunder the trade name GranuFoam® by Kinetic Concepts, Inc. of SanAntonio, Tex. Other layers may be included in or on the manifold 128,such as absorptive materials, wicking materials, hydrophobic materials,and hydrophilic materials.

The sealing drape 132 may be adapted to cover the second side 136 of themanifold 128 and to seal to a peripheral surface 138 proximate thetissue site 104. The peripheral surface 138 may be undamaged epidermis106 peripheral to the tissue site 104. In this manner, the sealing drape132 may provide a fluid seal between the sealing drape 132 and thetissue site 104 with the second side 136 of the manifold 128 facing thesealing drape 132. In some embodiments, the manifold 128 may bepositioned between the tissue site 104 and the sealing drape 132. Thefluid seal provided by the sealing drape 132 may be a seal adequate tohold reduced pressure at a desired tissue site given the particularreduced-pressure source involved. Thus, the sealing drape 132 mayprovide a sealed space 140 proximate to the tissue site 104 that may besubstantially isolated from the external environment and capable ofmaintaining reduced pressure.

The sealing drape 132 may comprise any material suitable for providingthe fluid seal described above. For example, the sealing drape 132 maycomprise one or more of the following materials: hydrophilicpolyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol;polyvinyl pyrrolidone; hydrophilic acrylics; hydrophilic siliconeelastomers; an INSPIRE 2301 material from Expopack Advanced Coatings ofWrexham, United Kingdom; a thin, uncoated polymer drape; naturalrubbers; polyisoprene; styrene butadiene rubber; chloroprene rubber;polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber;ethylene propylene diene monomer; chlorosulfonated polyethylene;polysulfide rubber; polyurethane (PU); EVA film; co-polyester;silicones; a silicone drape; a 3M Tegaderm® drape; a polyurethane (PU)drape such as one available from Avery Dennison Corporation of Pasadena,Calif.; polyether block polyamide copolymer (PEBAX), for example, fromArkema, France; or other appropriate material. Further, the sealingdrape 132 may be a hybrid drape formed of a combination of thepreviously described materials.

In some embodiments, the sealing drape 132 may be comprised of a liquidimpermeable material that may allow vapor and inhibit liquids fromexiting the sealed space 140 of the dressing 116. The sealing drape 132may be a flexible, breathable film having a high Moisture Vapor TransferRate (MVTR) of, for example, at least about 300 g/m² per 24 hours. Thesealing drape 132 may comprise a range of medically approved filmshaving a thickness between about 15 microns (μm) to about 50 microns(μm). In other embodiments, a low or no vapor transfer drape might beused.

In some embodiments, the dressing 116 may also include additional layers(not shown) that may be positioned between the tissue site 104 and thesealing drape 132. For example, the dressing 132 may include anabsorption layer, a tissue-interface layer, or additional manifoldlayers. The dressing 116 may also include an attachment device (notshown) capable of adhering or otherwise sealing the sealing drape 132 tothe peripheral surface 138. The attachment device may include, forexample, silicones and hot-melt adhesives. Other suitable attachmentdevices may include, for example, hydrogels and hydrocolloids.

Continuing with the embodiments of FIGS. 1-3, the porous conduit 120 mayinclude a central lumen 148, a first porous wall 152, a barrier layer156, and a second porous wall 160. The porous conduit 120 may be adaptedto be positioned in fluid communication with the manifold 128 and thesealed space 140. For example, the porous conduit 120 may be disposed inthe sealed space 140 in fluid communication with the manifold 128 andthe sealed space 140. As shown in the embodiment of FIG. 1, the porousconduit 120 may have an inserted length L into the sealed space 140 andan external circumference C that define an external surface area 142.The external surface area 142 may be in fluid communication with themanifold 128 and the sealed space 140. In some embodiments, the porousconduit 120 may be disposed into or around the manifold 128 with theexternal surface area 142 positioned in contact with the manifold 128.

The first porous wall 152 may be positioned substantially concentricabout the central lumen 148 and in fluid communication with the centrallumen 148. Further, the first porous wall 152 and the central lumen 148may each be in fluid communication with the manifold 128 and the sealedspace 140. For example, the first porous wall 152 may have an openporous structure defining a plurality of interconnected pores 164, shownin FIGS. 2 and 3, in fluid communication with one another. The openporous structure of the first porous wall 152 may be comprised of bondedparticles 168, shown in FIGS. 2 and 3, defining the interconnected pores164. The bonded particles 168 may be, for example, sintered polymerparticles or fibers. Thus, the interconnected pores 164 of the firstporous wall 152 may provide a plurality of fluid passageways through andalong the length of the first porous wall 152 that may be in fluidcommunication with the central lumen 148, the manifold 128, and thesealed space 140.

The barrier layer 156 may be positioned substantially concentric aboutthe first porous wall 152. The barrier layer 156 may be, for example,comprised of a material that is liquid impermeable and/or non-porous.The material comprising the barrier layer 156 may also be a hydrophobicmaterial. The barrier layer 156 may be applied as part of the porousconduit 120, for example, through a co-extrusion process or duringmolding. In some embodiments, an internal barrier layer (not shown) maybe disposed adjacent the first porous wall 152 within the central lumen148. The internal barrier layer may be comprised of a similar materialdescribed above for the barrier layer 156.

The second porous wall 160 may be positioned substantially concentricabout the barrier layer 156. Similar to the first porous wall 152, thesecond porous wall 160 may have an open porous structure defining aplurality of interconnected pores 172, shown in FIGS. 2 and 3, in fluidcommunication with one another. Further, the second porous wall 160 maybe comprised of bonded particles 176, shown in FIGS. 2 and 3, definingthe interconnected pores 172. Similar to the bonded particles 168 of thefirst porous wall 152, the bonded particles 176 of the second porouswall 160 may be, for example, sintered polymer particles or fibers. Alsosimilar to the first porous wall 152, the interconnected pores 172 ofthe second porous wall 160 may provide a plurality of fluid passagewaysthrough and along the length of the second porous wall 160 that may bein fluid communication with the manifold 128 and the sealed space 140.The barrier layer 156 may substantially preclude fluid communicationacross or through the barrier layer 156 in a lateral direction betweenthe first porous wall 152 and the second porous wall 160.

Continuing with FIGS. 1-3, the porous conduit 120 may have an insertionend 178, depicted in FIGS. 1 and 3, positioned within the sealed space140, and an external end 180, depicted in FIGS. 1 and 2, positionedexterior to the sealed space 140. Although the insertion end 178 isshown in a curved configuration in FIG. 1, the insertion end 178 mayextend straight or in any other suitable configuration within the sealedspace 140. The second porous wall 160 of the insertion end 178 maydefine the inserted length L and the external circumference C of theporous conduit 120 as described above. The external end 180 of theporous conduit 120 may additionally include an external barrier layer182 positioned substantially concentric about the second porous wall160. Similar to the barrier layer 156 described above, the externalbarrier layer 182 may be comprised of a liquid impermeable and/ornon-porous material that may also be a hydrophobic material. Theexternal end 180 of the porous conduit 120 may protrude through anaperture 184 in the sealing drape 132 to be coupled in fluidcommunication to the therapy device 124. A sealing collar 186 may besealingly engaged between the aperture 184 in the sealing drape 132 andthe external end 180 of the porous conduit 120. The porous conduit 120may be initially produced having the external barrier layer 182 appliedas described above, with the external barrier layer 182 beingsubsequently removed along the length L of the insertion end 178. Forexample, the external barrier layer 182 may be removed through variouspost production processes such as milling, laser etching, particleerosion, or cutting prior to inserting the insertion end 178 into thesealed space 140.

In other embodiments (not shown), additional lumens (not shown) may beintegrated into the porous conduit 120 as necessary to suit a particularapplication. For example, the central lumen 148 may be divided into twoor more smaller lumens that may be positioned in a substantially flatconfiguration beside one another. Such a configuration may enhancepatient comfort by providing a low profile for the porous conduit 120and the system 100 that may be less likely to snag on clothing and otherobstacles.

The therapy device 124 and the porous conduit 120 may be adapted to bein fluid communication with one another. As shown in FIG. 1, forexample, the external end 180 of the porous conduit 120 may be coupledin fluid communication to the therapy device 124. The therapy device 124may include a reduced-pressure source 188, a fluid instillation source190, and a pressure sensor 192. The reduced-pressure source 188 may becoupled in fluid communication with the central lumen 148. The fluidinstillation source 190 may be coupled in fluid communication with thefirst porous wall 152. The pressure sensor 192 may be coupled in fluidcommunication with the second porous wall 160. The reduced-pressuresource 188, the fluid instillation source 190, and the pressure sensor192 may be coupled in fluid communication to the components of theporous conduit 120 as described herein in any suitable manner. Forexample, the therapy device 124 may include a coupling (not shown)having fluid passageways adapted to provide fluid communication betweenthe central lumen 148 and the reduced-pressure source 188, between thefirst porous wall 152 and the fluid instillation source 190, and betweenthe second porous wall 160 and the pressure sensor 192.

The reduced-pressure source 188 may provide reduced pressure as a partof the system 100. The reduced-pressure source 188 may be any device forsupplying a reduced pressure, such as a vacuum pump, wall suction,micro-pump, or other source. As shown in FIG. 1, the reduced-pressuresource 188 may be housed within the therapy device 124. However, in someembodiments, the reduced-pressure source 188 may be a separate componentin fluid communication with the central lumen 148 of the porous conduit120. While the amount and nature of reduced pressure applied to a tissuesite may vary according to the treatment application, the reducedpressure may be between about −5 mm Hg (−667 Pa) to about −500 mm Hg(−66.7 kPa). In some embodiments, the reduced pressure may be betweenabout −75 mm Hg (−9.9 kPa) to about −300 mm Hg (−39.9 kPa).

The term reduced pressure may refer to a pressure less than the ambientpressure at the tissue site being subjected to treatment. The reducedpressure may be less than the atmospheric pressure, and less than ahydrostatic pressure at a tissue site. Unless otherwise indicated,values of pressure stated herein are gauge pressures. Consistent withthe use herein, an increase in reduced pressure or vacuum pressure mayrefer to a relative reduction in absolute pressure.

As shown in FIG. 1, the fluid instillation source 190 may be housedwithin the therapy device 124. However, in some embodiments, the fluidinstillation source 190 may be a separate component that may be in fluidcommunication with the first porous wall 152 of the porous conduit 120.The fluid instillation source 190 may be any device capable ofcontaining and supplying a fluid for instillation in the system 100,such as, for example, a bladder or intravenous (IV) bag. Theinstillation fluid may be, for example, medications, anti-bacterials,growth factors, and other solutions as described above.

Further, as shown in FIG. 1, the pressure sensor 192 may be housedwithin the therapy device 124. However, in some embodiments, thepressure sensor 192 may be a separate component that may be in fluidcommunication with the second porous wall 160 of the porous conduit 120.The pressure sensor 192 may be any device suitable for sensing a reducedpressure and providing a pressure signal corresponding to the reducedpressure. In some embodiments, an indicator dye (not shown) may beincluded in the second porous wall 160 to indicate to a user that thesecond porous wall 160 has been exposed to fluid that could disrupt thepressure signal from the pressure sensor 192. For example, the indicatordye may be a material adapted to provide a color change when broughtinto contact with a liquid. The indicator dye may, for example, bedisposed in at least a portion of the interconnected pores 172 of thesecond porous wall 160. The indicator dye may be utilized in othercomponents of the system 100 without limitation.

In some embodiments, the porous conduit 120 may have a variety of shapesand geometries to suit a particular application. For example, geometriessuch as ovals, rectangles, and polygons may be utilized for thecross-sectional shape of the porous conduit 120. As shown in FIG. 4, anexternal end 280 of a porous conduit 220 may include a plurality oflongitudinal depressions 194 and a plurality of longitudinal protrusions196 suitable for use with the system 100. The longitudinal depressions194 and the longitudinal protrusions 196 may be disposed about anexternal circumference C′ of the porous conduit 220 and extendlengthwise along a length of the porous conduit 220. The porous conduit220 may retain substantially the same structure and function of thepreviously described central lumen 148, the first porous wall 152, thebarrier layer 156, the second porous wall 160, the external barrierlayer 182, and other components of the porous conduit 120. Further, theporous conduit 220 may retain substantially the same integration as thepreviously described porous conduit 120 within the system 100. However,the longitudinal depressions 194 and the longitudinal protrusions 196 ofthe porous conduit 220 may provide additional external surface area forenhancing fluid communication, for example, with the sealed space 140and the manifold 128 in the system 100.

In other embodiments, the porous conduit 120 may have any number ofporous walls, analogous to the first and the second porous walls 152,160, to suit a particular application. Likewise, barrier layers in theporous conduit 120 that may be analogous to the barrier layer 156 andthe external barrier layer 182 may be added or omitted as necessary. Forexample, FIG. 5 illustrates another embodiment of a porous conduit 320suitable for use in the system 100 in substantially the same manner asdescribed above for the porous conduit 120. The porous conduit 320 mayinclude the central lumen 148 and a porous wall 360 positionedsubstantially concentric about the central lumen 148 and in fluidcommunication with the central lumen 148. The central lumen 148 and theporous wall 360 may be positioned as described above in fluidcommunication with the sealed space 140 and the manifold 128. The porouswall 360 may have the same open porous structure and may be comprised ofthe same materials described above for the first porous wall 152 and thesecond porous wall 160. As described above, the central lumen 148 may becoupled in fluid communication with the reduced-pressure source 188.Analogous to the first and the second porous wall 152, 160, the porouswall 360 may be coupled in fluid communication with the pressure sensor192 and/or the fluid instillation source 190 in the therapy device 124as desired. Also analogous to the porous conduit 120, an external end380 of the porous conduit 320 that may be adapted to be positionedexterior to the sealed space 140 may include an external barrier layer382 comprised of substantially the same materials and havingsubstantially the same structure as the external barrier layer 182.

Referring generally to FIG. 6, provided is an illustrative embodiment ofa system 400 wherein the porous conduit 120 may be adapted for use witha conduit interface 495 and a multiple lumen conduit 497. The system 400may be substantially similar in structure and function as the system100. However, in the system 400, the insertion end 178 of the porousconduit 120 may be coupled in fluid communication with the conduitinterface 495. Further, the insertion end 178 of the porous conduit 120may be positioned in a substantially straight configuration within thesealed space 140.

Continuing with FIG. 6, the conduit interface 495 may be adapted to becoupled in fluid communication between the porous conduit 120 and thetherapy device 124. As described above, the porous conduit 120 may bepositioned in the sealed space 140 proximate the aperture 184 in thesealing drape 132. The conduit interface 495 may be coupled to theporous conduit 120 through the aperture 184 and may sealingly engage thesealing drape 132 about the aperture 184. Other embodiments (not shown)may include an external end of the porous conduit 120, analogous to theexternal end 180 depicted in FIG. 1, that may be adapted to bepositioned exterior to the sealed space 140 and coupled in fluidcommunication to the conduit interface 495. In such an embodiment, theconduit interface 495 may remain separate from the sealing drape 132.

The conduit interface 495 may include a reduced-pressure lumen 448 athat may be in fluid communication between the central lumen 148 and thereduced-pressure source 188. Further, the conduit interface 495 mayinclude a fluid instillation lumen 452 a that may be in fluidcommunication between the first porous wall 152 and the fluidinstillation source 190.

Additionally, the conduit interface 495 may include a sensing lumen 460a that may be in fluid communication between the second porous wall 160and the pressure sensor 192. The conduit interface 495 may include anynumber of lumens as appropriate for providing fluid communication amongembodiments of the porous conduit, the multiple lumen conduit, and thetherapy device according to this disclosure.

The multiple lumen conduit 497 may be adapted to be coupled in fluidcommunication between the conduit interface 495 and the therapy device124. Analogous to the conduit interface 495, the multiple lumen conduit497 may include a reduced-pressure lumen 448 b that may be in fluidcommunication between the central lumen 148 and the reduced-pressuresource 188. Further, the multiple lumen conduit 497 may include a fluidinstillation lumen 452 b that may be in fluid communication between thefirst porous wall 152 and the fluid instillation source 190.Additionally, the multiple lumen conduit 497 may include a sensing lumen460 b that may be in fluid communication between the second porous wall160 and the pressure sensor 192. The reduced-pressure lumen 448 b, thefluid instillation lumen 452 b, and the sensing lumen 460 b of themultiple lumen conduit 497 may be in fluid communication with thereduced-pressure lumen 448 a, the fluid instillation lumen 452 a, andthe sensing lumen 460 a of the conduit interface 495, respectively. Themultiple lumen conduit 497 may include any number of lumens asappropriate for providing fluid communication among embodiments of theporous conduit, the conduit interface, and the therapy device accordingto this disclosure.

In operation, the system 100 may be applied to a patient in theoperating room after a surgical procedure or elsewhere. According to oneillustrative embodiment, the manifold 128 may be placed proximate to thetissue site 104. The manifold 128 may be placed within the tissue site104, or may overlay a portion of the tissue site 104. The sealing drape132 may be placed over the manifold 128 such that a portion of thesealing drape 132 overlays the peripheral surface 138 around the tissuesite 104. The sealing drape 132 may be secured to the peripheral surface138 in order to form the sealed space 140 between the tissue site 104and the sealing drape 132 described above. The fluid seal forming thesealed space 140 need only be adequate to allow the system 100 tomaintain a reduced pressure at the tissue site 104 for a desiredtreatment time. The individual components of the dressing 116 may besized according to the particular application or the procedure beingperformed by a healthcare provider. For example, the components of thedressing 116 may be sized, shaped, and configured to work in differentanatomical applications such as the abdomen, chest, thighs, hip, etc.

The porous conduit 120 may be fed through the aperture 184 in thesealing drape 132 and pushed into the manifold 128, or fed between themanifold 128 and the tissue site 104. To assist with the application ofthe system 100, the manifold 128 may be pre-cut with holes (not shown)sized to receive the porous conduit 120. In some embodiments, the porousconduit 120 may be routed around the tissue site 104 and the manifold128 may be subsequently applied allowing for a portion of the porousconduit 120 to be positioned proximate the aperture 184 to facilitateconnection with the therapy device 124.

As described above, the porous conduit 120 may be coupled in fluidcommunication to the therapy device 124 utilizing, for example, theexternal end 180 of the porous conduit 120, or the conduit interface 495and the multiple lumen conduit 497. The reduced-pressure source 188 maythen be activated to deliver reduced pressure to the sealed space 140.

Upon application of the reduced pressure to the dressing 116 through theporous conduit 120, fluids from the tissue site 104 may be drawn intothe manifold 128 and the porous conduit 120. In some embodiments, thesystem 100 may include a fluid canister (not shown) positioned in fluidcommunication between the central lumen 148 in the porous conduit 120and the reduced-pressure source 188 in the therapy device 124 forcapturing excess fluids. As fluids from the tissue site 104 enter thecentral lumen 148, the fluids may cause blockages by, for example,gelling or otherwise thickening within the central lumen 148. Theinterconnected pores 164 in the first porous wall 152 may provide aplurality of alternate fluid communication passageways that may beresistant to such blockages. Further, should a blockage occur in thefirst porous wall 152, the interconnected pores 164 and correspondingpassageways may be sufficiently numerous to maintain fluid communicationwith the sealed space 140. In this manner, reduced pressure therapy maybe reliably maintained with the tissue site 104. Further, instillationfluids from the instillation fluid source 190 that may be in fluidcommunication with the first porous wall 152 may travel reliabilitythrough the interconnected pores 164 to the tissue site 104. Similar tothe interconnected pores 164 of the first porous wall 152, theinterconnected pores 172 of the second porous wall 160 may provide aplurality of alternate fluid communication passageways that may benumerous and resistant to blockages. In this manner, the pressure sensor192 that may be in fluid communication with the second porous wall 160may provide an accurate pressure signal corresponding to the reducedpressure in the sealed space 140 of the dressing 116 for reliablycontrolling the reduced pressure. Further, the external surface area 142of the insertion end 178 of the porous conduit 120 being disposed in thesealed space 140 and in fluid communication between the sealed space 140and the pressure sensor 192 may enhance the reliability of the pressuresignal generated by the pressure sensor 192.

Although this specification discloses advantages in the context ofcertain illustrative, non-limiting embodiments, various changes,substitutions, permutations, and alterations may be made withoutdeparting from the scope of the specification as defined by the appendedclaims. Further, any feature described in connection with any oneembodiment may also be applicable to any other embodiment.

We claim:
 1. A system for treating a tissue site, comprising: a manifoldconfigured to be positioned proximate the tissue site; a cover layerconfigured to cover the manifold and the tissue site to provide a sealedspace between the cover layer and the tissue site; a porous conduitconfigured to be disposed in the sealed space in fluid communicationwith the manifold and the sealed space, comprising: a lumen, a firstporous wall positioned substantially concentric about the lumen; and asecond porous wall positioned substantially concentric about the firstporous wall; and a therapy device adapted to be in fluid communicationwith the porous conduit, the therapy device comprising areduced-pressure source configured to be in fluid communication with thelumen.
 2. The system of claim 1, wherein the manifold is adapted todistribute reduced pressure to the tissue site, and wherein the manifoldis comprised of a porous, hydrophobic foam.
 3. The system of claim 1,wherein the cover layer is comprised of a liquid impermeable material.4. The system of claim 1, wherein the first porous wall and the secondporous wall have an open porous structure defining a plurality ofinterconnected pores in fluid communication with one another.
 5. Thesystem of claim 4, wherein the first porous wall and the second porouswall are comprised of bonded particles that define the interconnectedpores of the first porous wall and the interconnected pores of thesecond porous wall.
 6. The system of claim 5, wherein the bondedparticles are sintered polymer particles.
 7. The system of claim 1,wherein the therapy device further comprises a pressure sensorconfigured to be in fluid communication with the second porous wall. 8.The system of claim 1, wherein the therapy device further comprises afluid instillation source in fluid communication with the first porouswall.
 9. The system of claim 1, further comprising a barrier layersubstantially concentric about the first porous wall, wherein thebarrier layer is comprised of a non-porous material.
 10. The system ofclaim 9, wherein the non-porous material is liquid impermeable andhydrophobic.
 11. The system of claim 1, wherein the porous conduit hasan insertion end positioned within the sealed space and an external endpositioned exterior to the sealed space, the external end coupled influid communication to the therapy device.
 12. The system of claim 11,wherein the external end further comprises an external barrier layer,wherein the external barrier layer is comprised of a non-porous, liquidimpermeable material.
 13. The system of claim 1, wherein the lumencomprises two or more lumens.
 14. The system of claim 1, wherein theporous conduit has an external surface comprising a plurality oflongitudinal depressions and a plurality of longitudinal protrusionsdisposed about an external circumference of the porous conduit andextending lengthwise along a length of the porous conduit.
 15. Thesystem of claim 1, wherein the porous conduit has an ovalcross-sectional shape.
 16. The system of claim 1, wherein the porousconduit has a length and an external circumference defining an externalsurface area that is disposed in the sealed space and in fluidcommunication with the manifold and the sealed space.
 17. The system ofclaim 16, wherein the second porous wall defines the length and theexternal circumference of the porous conduit.
 18. The system of claim 1,further comprising a conduit interface adapted to be coupled in fluidcommunication between the porous conduit and the therapy device, whereinthe porous conduit is positioned in the sealed space proximate anaperture in the cover layer, and wherein the conduit interface isadapted to be coupled to the porous conduit through the aperture, andwherein the conduit interface is adapted to sealingly engage the coverlayer about the aperture in the cover layer.
 19. The system of claim 18,further comprising a multiple lumen conduit coupled in fluidcommunication between the conduit interface and the therapy device,wherein the therapy device further comprises a fluid instillation sourceand a pressure sensor, and wherein the conduit interface and themultiple lumen conduit each provide a reduced-pressure lumen in fluidcommunication between the lumen and the reduced-pressure source, a fluidinstillation lumen in fluid communication between the first porous walland the fluid instillation source, and a sensing lumen in fluidcommunication between the second porous wall and the pressure sensor.20. The system of claim 1, wherein the porous conduit is disposed intothe manifold.
 21. The system of claim 1, wherein the porous conduit isdisposed in the sealed space.
 22. An apparatus for managing fluid from atissue site, comprising: a lumen; a first porous wall positionedsubstantially concentric about the lumen, wherein the first porous wallhas an open porous structure defining a plurality of interconnectedpores in fluid communication with one another; and a second porous wallpositioned substantially concentric about the first porous wall, whereinthe second porous wall has an open porous structure defining a pluralityof interconnected pores in fluid communication with one another.
 23. Theapparatus of claim 22, wherein the first porous wall and the secondporous wall are each comprised of bonded particles that define theinterconnected pores of the first porous wall and the interconnectedpores of the second porous wall.
 24. The apparatus of claim 22, furthercomprising a barrier layer positioned substantially concentric about thefirst porous wall.
 25. The apparatus of claim 24, wherein the barrierlayer is comprised of a non-porous material.
 26. The apparatus of claim25, wherein the non-porous material is liquid impermeable andhydrophobic.
 27. The apparatus of claim 22, wherein the apparatus has aninsertion end and an external end, the external end further comprisingan external barrier layer positioned substantially concentric about thesecond porous wall, wherein the external barrier layer is comprised of anon-porous, liquid impermeable material.
 28. The apparatus of claim 22,wherein the lumen comprises two or more lumens.